Lubrication



NOV. ll, 1941. M FA|R| |E ErAL 2,262,528

LUBRICATION Filed July l5, 1938 ffy/he ATTORNEYS Patented Nov. il, T941 jaar,"

LUBRICATTON Matthew Fair-lie and Leonard 1E. Beate, Hammond, Ind., assignors to Sinclair Refining Company, New York, N. Y., a corporation of Maine Application July 15, 1938, Serial No. 219,458

11 Claims.

This invention relates to lubrication and particularly to lubrication employing petroleumbase oils. The invention aims to prolong the useful life of such oils, inhibit formation of carbon, sludge, tars, asphaltenes, and organic acids and other injurious products in'such oils during service and to substantially reduce piston lacquering, ring-sticking and bearing corrosion in internal combustion engines and the like in which petroleum-base oils are employed as lubricants, by subjecting such oils, after or during service, to the action of at least two alkaline earth metals in elemental or combined inorganic form.

As described and claimed in our co-pending application, Serial No. 219,457, filed July 15, 1938, We have discovered that if petroleum-base oils, either compounded or uncompounded, are

heated substantially above normal crank case temperature and passed in contact with a solid selected from the group consisting of the alkaline earth metals and their inorganic com.- pounds, the tendency of the oil to deteriorate during service is reduced and mechanical diiculties, particularly ring-sticking, are inhibited. In another copending application, Serial No. 219,456, filed July 15, 1938, we have described and claimed our discovery that contact masses of alkaline earth metals or inorganic compounds thereof are very eiective in preventing deterioration of and corrosion by petroleum base oils containing a soap of an alkaline earth metal even at relatively low temperatures. In a third copending application, Serial No. 219,459, led July 15, 1938, we have described and claimed our discovery that contact masses of alkaline earth metals or inorganic compounds thereof are likewise effective in preventing deleterious action of petroleum-base oils containing an aluminum soap. i

We have discovered also that mixtures containing more than one of the three alkaline earth metals (i. e., calcium, barium and strontium) in elemental or combined inorganic form manifest increased eiectiveness in inhibiting deterioration of petroleum-base oils and preventing corrosion thereby, as compared with contact masses containing only one of the alkaline earth metals in combined or elemental form. Thus, We have discovered that a mixture of calcium hydroxide and barium hydroxide is more effective as a corrosion inhibiter and for preventing ring-sticking,l piston lacquering and other mechanical diiculties in internal combustion enf gines than is an equal quantity of either calcium hydroxide or Similarly, mixtures containing both calcium and strontium in elemental or combined inorganic form or mixtures containing both strontium and 4barium in elemental or combined inorganic form make a more effective contact mass than do any of the three alkaline earth metals taken alone, whether in elemental form or combined as an inorganic solid.

Our invention, therefore, contemplates the treatment of a petroleum base lubricant by passing it in contact with a mass containing at least two alkaline earth metals in the form of solids selected from the group consisting of the alkaline earth metals and their inorganic compounds. Preferably, the substance is in porous or finely-divided. form so that the oil may be passedthrough it. Thus, the solid or contact may be in the form of a filter disposed in the lubricating system of a machine, the oil being pumped out of the service zone of the `machine, say a crank case of an internal comthe filter and back into l bustion engine, through the service zone. The effectiveness of the contact mass containing at least two alkaline earth metals in combined or elemental inorganic form v is increased within limits as the temperature of the oil in contact with the mass is increased.

Our invention will be understood more thoroughly in the light of the following detailed description taken in conjunction with the accompanying single gure which shows in vertical -section an appropriate filter containing a contact mass in which at least two alkaline earth metals are present in elementalor combined inorganic form, this filter being connected in the lubricating system of an internal combustion engine, which is shown schematically.

Referring now to the drawing, it will be seen that the filter comprises ra cylindrical metal shell Ill having a cover plate ll bolted to a flange l2 around the top of the shell with a gasket I3 interposed between the flange and the top to insure a tight joint. Disposed concentrically within the shell is a canister l made of perforated Monel metal screen or other pervious cor-f rosion-resistant material.

The canister isv annular in form with an enclosing top portion l5A so that it surrounds a space i6 immediately above an outlet pipe Il. An inlet pipe i8 is provided in the outside of the shell and the space in the shell around the canister is filled with cotton wool I9 or other inert filter medium.4 `The inside of the canister is filled with a pervious mass 20 of an inorganic solid containing in elebarium hydroxidev alone.

`lter on the engine.

Y the lubricating system mental or inorganic combined form at least two of the alkaline earthfmetals-calcium, strontium and barium. Thus, the canister may be packed withja mixture of twisted calcium and barium foil. or a mixture containing two or ymore ofr the alkaline earth metals in combined form., for example, as oxides, carbonates, hydroxides, or carbides. For economic reasons, it is desirable to lll the canister with fine lumps (say 8 to 14 mesh) of calcium hydroxide together with an inorganic compound of strontium yor barium or both. Barium and strontium hydroxides should be employed in anhydrous form, because in the crystalline form they lose water at relatively low temperatures.

Oil is withdrawn from the crank case of the engine and by means of a pump yforced through l. of either barium hydroxide or strontium hydrox-y tium or barium. Thus, a contact mass containing two-thirds calcium hydroxide and one-third ide has given best results in inhibiting ring-sticking and preventing bearing corrosion.

We give below a summary of results obtained with contact masses containing two alkaline earth metals as compared with the results obtained when a mass containing only one-of the the cotton wool and the contact mass to the outlet of the filter, from which point the treated oil is returned to the crank case so that a repeated circulation is set up. I

The tendency of the contact mass to escape from the filter is relatively slight. Lumps of the `hydroxides of the alkaline earth metals are relatively friable in the air, but when once wetted with oil, there is little tendency yfor them to break apart. However, the cotton wool or other filter media is providedas a safeguard against the circulation of the hydroxides or other solids through the engine. The cotton also serves to distribute the oil through the contact mass and thus prevent channeling. y

As a further precaution against the escape of the contact mass into the engine, it is advisable to soak the mass with oil prior to installing the 'This may be done conveniently by pumping oil through the mass, so that une, particles which tend to escape may be removed prior to placing the mass in service in the lubricating system.

As shown, heating means may be provided in preferably ahead of or adjacent to the contact mass so that the oil may be heated to an optimumtemperature prior to or during contact with the mass. Within limits established by thethermal stability" of the particular oil employed, higher temperatures promoteA improved action of the contact mass.

Extensive tests indicate that the most desirable contact mass both from the standpoint of econmetals was employed and with results when no contact mass was used. Barium hydroxide alone is slightly inferior to either strontium hydroxide or calcium hydroxide from the standpoint of inhibiting ring-sticking. It is, however, superior to the hydroxides of these other two alkaline metals from the standpoint of preventing bearing corrosion by uncompounded oils. Hence, barium hydroxide alone is superior as a contact mass to either of the other hydroxides taken alone, but as the following results show, is inferior to mixtures containing any two of the alkaline earth metal hydroxides from the standpoint of inhibiting ring-sticking and preventing bearing corrosion, which are the most important factors in the lubrication of modern internal combustion engines.

In all cases, the test procedure was exactly the same except insofar as the contact mass is concerned, and in the temperature of contact. The oil subjected to test was a high-grade uncompounded Pennsylvania lubricating oil adapted for y aircraft service. It was Acirculated through the lubricating system of a gasoline engine, the oil being pumped from the crank case of the engine through a lter and thence returned to the crank case. In Tests 2 to '7, inclusive, the contact mass comprised hydroxide pellets ranging in size from that of a pea down to about 14 mesh. In all cases the total oil in the lubricating system ramounted to ,about '7 liters, audit was circulated through the lter at the rate of about three liters per minute. In each instance the contact mass weighed about 800 to 2000 grams depending on composition. The oil pressure was 15 pounds per square inch in each instance and the pressure drop in the filter ranged from 3 to 8 pounds per square inch. All tests were run for fifty hours, and thereafter the engine was taken down; bearing corrosion was determined; carbon deposits were removed, weighed and examined, and the used oil was subjected to analysis.

Test No 1 2 3 4 5 6 7 (CBOHM, 1% Sr(OH)2, Ca(OH)z, 5 Ca(0H)z, 95 Ca(0H)z, Contact mSS Used None B8(OH)2 56 Ba OH z %Ba(OH)Z %Sr(OH)as %Sr(OH)zts %sr(oH)zen Temp. of contact F +2S0290 290 290 280-290 280-290 28o-290 240 Analysis of used oil percent Carb0n" 3. 310 1. 69 1- 82 l. 93 2. 17 l. 88 Percent tar 0. 268 0, 184 0. 204 O. 236 0. 156 0. 216 0. 160 Percent asphaltenes. 0, 148 0. 048 0. 040 0. O72 0. 072 0. 144 0. 088 Piston deposits, gms 2. 274 3.054 3- 264 1. 561 2. 8131 1.195 2. 902 Bearing loss, s:

Cadmiums1lverz f A 2. 051 0. v293 0. 023 0. 094 0. 209 0. 058 0. 437 B 2. 443 0. 401 0. 068 0. 119 0. 225 0. 064 0. 499 Copper lead:

A 0. 405 0. 358 0. 063 O. 246 0. 139 0. 105 0. 147 0. 404 0. 322 0. 0. 144 0. 103 0. 064 0. 101 0. 055 0. 014 0. 007 0. 027 0. 012 0. 013 0. 067 0. 048 0. O17 0. 012 0. 008 0. 010 0. 007 0. 007 0. 089 0. 015 0. 007 0. 030 0. 066 0. 025 0. 017 o. 059 o. 01a o. 009 0.006 0.011 o. 009 o. 005 Ring rating percent free 73. 3 87. 0 94. 2 97. 5 75. 8 100. 0 87. 1 Character oi' carbon f formed Hard .4 Semi-friable- Very hard.-. Frieble Hard Prepared by mixing alkaline earth oxides before hydration. Alkaline earth oxides hydrated and dried, then mixed to form mass. +Temperature of oil as returned to crank case without contact with mass.

my and of efficiency is one containing about twor parts of calcium for each part of either stron- As the foregoing results show, mixtures containing more than one alkaline earth metal are formed.

treating zone to maintain the oil in contact with to be preferred over contact mass containing only one alkaline earth metal. Bearing corrosion is reduced when using the mixed contact masses with bearings such as cadmium-silver, which are very susceptible to corrosion and also with the relatively corrosion-resistant materials such as babbitt.

The benefits to be obtained by using the mixed contact mass are increased with increased temperature. This is shown by a comparison of the results of Tests 6 and 7. The conditions in these two tests were identical except that the contact temperature in Test 6 was 280- 290 F., as contrasted with a contact temperature of 240 F. in Test 7. In consequence of the increased temperature in Test 6, ring-sticking was completely eliminated and corrosion of the three kinds of bearing metals tested was substantially decreased.

A comparison of the results of Tests and 6 shows that it is desirable to mix the alkaline earth hydroxide employed from the mass after hydration of the oxides from which they are In Test 5 the, mass was prepared by mixing calcium oxide with strontium oxide and then hydrating and drying the mixture. This procedure is shown to be less satisfactory than the procedure in Test 6 in which the alkaline earth hydroxides are first hydrated and. dried and then mixed. Preparation of the contact mass by mixing the alkaline earth oxides prior to hydration is unfavorable in another respect in that a mass thus formed tends to produce hard carbon which apparently tends to cause ringsticking,

The tendency toward forming hard carbon with consequent tendency toward ring-sticking is also increased with a decrease in contact temperature as a comparison of the results of Tests 6 and 7 clearly shows.

We claim:

1.v In the-operation of a system for lubricating a machine with a petroleum base lubricating oil which involves repeated contacting of said oil from a body thereof with the surfaces to be lubricated and circulation of said oil during service through a treating zone, the improvement which comprises passing the oil in said treating zone through a contact mass containing at least two of the alkaline earth metals in the form of solids selected from the group consisting of the alkaline earth metals and inorganic compounds,

thereof, at a rate sufficient to bring into contact with said solids an amount of oil equivalent to a substantial part of said body of loll per minute, and controlling the temperature of the oil in said said contact mass at a temperature approximating 240-290 F.

2. The process of claim 1 in which the contact mass contains at least two of the alkaline earth metal hydroxides.

3. The process of claim 1 in which the contact mass contains calcium hydroxide and barium hydroxide.

4. The process of claim 1 in which the contact mass contains calcium hydroxide and strontium hydroxide.

5. 'I'he process of claim 1 in which the contact mass contains barium hydroxide an strontium hydroxide.

6. The process of claim 1 in which the contact mass contains calcium hydroxide and at least one other alkaline earth hydroxide, the calcium hydroxide being present in an amount exceeding the other alkaline earth metal hydroxide,

7. Theprocess of claim 1 in which the contact mass contains calcium hydroxide and barium hydroxide, the amount of calcium hydroxide present being about twice the amount ofbarium hydroxide present.

8. The process of claim 1 in which the contact mass contains calcium hydroxide and strontium hydroxide, the amount of calcium hydroxide present being about twice the amount of strontium hydroxide present.

9. The process of claim 1 in which the contact mass contains at least two of the'alkaline earth metals hydroxide and in which the oil is brought into contact therewith at a temperature of about 290 F.

10. 'I'he process of claim I1 in which the contact mass contains at least two of the alkaline earth metal hydroxides having a particle size ranging from that of a pea to about 14 mesh.`

11. In the operation of a system for lubricating a machine with a petroleum base'lubricating oil which involves repeated contacting of said oil from a body thereof with the surfaces to be lubricated and circulation of said oil during service through a treating zone, the improvement which comprises heating the oil and passing it in said treating zone through a contact mass containing at least two of the alkaline earth metals in the form of solids selected from the group consisting of the alkaline earth metals andv inorganic compounds thereof at a rate sufficient to bring into contact with said solvent an amount of oil equivalent to approximately of said body of oil per minute. K MA'II'HEW FAIRLIE.

LEONARD E. BEARE. 

